There are about 170 species of swertia in the world, of which there are about 35 medicinal plants. China has an estimated 80 species, north and south is distribution, according to the literature and folk swertia genus application, about 24 species of the genus medicine, can be divided into the steamed bravery, swertia genera, pedicle of class (Tigta), Chiraita and Japan as medicine.